Chapter 17

Question 1

occur when the second pharyngeal arch fails to grow caudally over the third and fourth arches, leaving remnants of the second, third, and fourth clefts in contact with the surface by a narrow canal

Answer 1

Branchial Fistulas

Question 2

a fistula, found on the lateral aspect of the neck directly anterior to the sternocleidomastoid muscle, usually provides drainage for a lateral cervical cyst

Answer 2

Branchial Fistula

Question 3

cysts that are remnants of the cervical sinus, are most often just below the angle of the jaw, although they may be found anywhere along the anterior bor- der of the sternocleidomastoid muscle.

Answer 3

Lateral cervical cyst

Question 4

are rare; they occur when the cervical sinus is connected to the lumen of the pharynx by a small canal, which usually opens in the tonsillar region

Answer 4

Internal branchial fistulas

Question 5

fistula resulting from a rupture of the membrane between the second pharyngeal cleft and pouch at some time during development.

Answer 5

Internal brachial fistula

Question 6

Cells that are essential for formation of much of the craniofacial region.

Answer 6

Neural crest cells

Question 7

septate the outflow tract of the heart into pulmonary and aortic channels

Answer 7

Conotruncal endocardial cushions

Question 8

The syndrome is characterized by hypoplasia of the maxilla, mandible, and zygomatic arches, which may be absent.

Answer 8

Treacher Collins Syndrome (mandibulofavial dysostpsis

Question 9

Mutations of whhic gene are responsiple for the Treacher Collins syndrome

Answer 9

TCOF1 gene (5q32)

Question 10

The product of TCOF1 gene that appears to be necessary for preventing apoptosis and maintaining proliferation in neural crest cells but not for regulating their migration, which occurs normally.

Answer 10

Treacle

Question 11

Exposure to which teratogenic can produce phenocpies of the treacle

Answer 11

Retinoic acid

Question 12

may occur independently or in association with other syndromes and malformations. Like Treacher Collins syndrome, this sequence alters first-arch structures, with development of the mandible most severely affected.

Answer 12

Robin sequence

Question 13

posteriorly placed tongue]

Answer 13

Glossoptosis

Question 14

is the most common deletion syndrome in humans and has several presentations, including DiGeorge syndrome, DiGeorge anomaly, ve-locardiofacial syndrome, Shprintzen syndrome, conotruncal anomaly face syndrome, and congenital thymic aplasia and hypoplasia.

Answer 14

22q11.2 Deletion syndrome

Question 15

Mutations in what gene result in the same syndrome (2aq11.2 Deletion syndrome) without a deletion

Answer 15

TBX1

Question 16

cells from the pouches that make the thymus and parathyroid cells

Answer 16

Endpderm cells

Question 17

Includes a number of craniofacial abnormalities that usually involve the maxillary, temporal, and zygomatic bones, which are small and flat.

Answer 17

Hemifacial microsomia [oculoauriculovertebral spectrum or Goldenhar syndrome]

Question 18

the tongue is not freed from the floor of the mouth.

Answer 18

Ankyloglossia (tongue-tie)

Question 19

the only tissue that anchors the tongue to the floor of the mouth

Answer 19

Frenulum

Question 20

may lie at any point along the migratory pathway of the thyroid gland but is always near or in the midline of the neck.

Answer 20

Thyroglossal cyst

Question 21

it is a cystic remnant of the thyroglossal duct.

Answer 21

Thyroglossal cyst

Question 22

fistula usually arises secondarily after rupture of a cyst but may be present at birth.

Answer 22

Thyroglossal fistula

Question 23

may be found anywhere along the path of descent of the thyroid gland. It is commonly found in the base of the tongue, just behind the foramen cecum, and is subject to the same diseases as the thyroid gland itself

Answer 23

Aberrant thyroid tissue

Question 24

Are common defects that result in abnormal facial appearance and difficulties with speech

Answer 24

Cleft lip and cleft palate

Question 25

considered the dividing landmark between anterior and posterior cleft deformities.

Answer 25

Incisive foramen

Question 26

include lateral cleft lip, cleft upperjaw, and cleft between the primary and secondary palate

Answer 26

Anterior to the incisive foramen

Question 27

Such defects are due to a partial or complete lack of fusion of the maxillary prominence with the medial nasal prominence on one or both sides.

Answer 27

Those anterior to the incisive foramen

Question 28

include cleft [secondary] palate and cleft uvula

Answer 28

Lie posterior to the incisive foramen

Question 29

results from a lack of fusion of the palatine shelves, which may be due to small- ness of the shelves, failure of the shelves to elevate, inhibition of the fusion process itself, or failure of the tongue to drop from between the shelves because of micrognathia

Answer 29

Cleft palate

Question 30

the most com- mon syndrome associated with cleft lip with or without cleft palate

Answer 30

Van der Woude syndrome

Question 31

Mutated genes in the van der woude syndrome

Answer 31

Interferon regulatory factor 6

Question 32

produced by failure of the maxillary prominence to merge with its corresponding lateral nasal prominence along the line of the nasolacrimal groove. When this occurs, the nasolacrimal duct is usually exposed to the surface

Answer 32

Oblique facial clefts

Question 33

a rare abnormality, caused by incomplete merging of the two medial nasal prominences in the midline

Answer 33

Median (midline) cleft lip

Question 34

Loss of midline tissue may be so extensive that the lateral ventricles fuse resulting to

Answer 34

Holoprosencephaly

Question 35

occurs more frequently in males [65%] than in females, and its incidence varies among populations. Asians and Native Americans have some of the highest rates [3.5/1,000], whereas African Americans have the lowest [1/1,000].

Answer 35

Cleft lip with or without cleft palate

Question 36

occurs more often in females [55%] than in males; In females, the palatal shelves fuse approximately 1 week later than in males,

Answer 36

Isolated cleft palate

Question 37

erupted by the time of birth. Usually, they involve the mandibular incisors, which may be abnormally formed and have little enamel.

Answer 37

Natal teeth

Question 38

Cause of discoloration of the teeth

Answer 38

Tetracyclines

Question 39

deficiency in enamel is often caused by

Answer 39

Vitamin D deficiency